An increasing number of software and hardware based computer systems are using Automatic Speech Recognition (ASR) technology to allow a user to navigate through and control a wide variety of applications via speech input. ASR systems recognize speech input, and map user utterance to tokens based on a grammar that defines allowable speech inputs and rules for interpreting the speech. These tokens can then be processed by an application program.
ASR technology is powerful, but not fool-proof. That is, ASR systems do not always correctly recognize the user's utterance. This can occur due to a variety of factors including noisy environments, the speaker's accent and mispronunciation, microphone quality, etc.
ASR systems function by matching the user's utterance against a grammar that defines the allowable words and phrases. The result of the ASR processing is a one or more matching tokens, each with a corresponding measure of confidence that the user's utterance matches the text token. The presence of more than one matching token indicates that there is no clear best match to the user's speech. We refer to the process of accurately determining the user's intent using the list of returned matches (and the corresponding confidence values) as “disambiguation.”
Current voice based disambiguation mechanisms suffer from many limitations. Often the user is asked to repeat his utterance, which may lead to the same un-matched result. Sometimes, the list of alternatives is spoken back to the user using Text-to-Speech (TTS) technology. This is slow, and with poor TTS quality, the user may misinterpret the alternatives. This often results in user frustration, and is a slow and cumbersome process especially when the ASR engine is remote to the user (as is often the case with mobile scenarios).
Multimodal interfaces represent a new technology that facilitates the use of multiple modalities (or modes) to interact with an application. Multi-modal interfaces are potentially useful in improving the disambiguating of speech and substantially improving end user experience.
In view of the foregoing, there is a need for a system that overcomes the drawbacks of the prior art.